1. Field of the Invention
This invention relates generally to farming row crop applicators having adjustable track widths, and more specifically to row crop applicators having adjustable length tie rods adapted to the steerable axle.
2. Description of the Prior Art
Row crop applicators are widely used in the farming industry for applying fertilizer about a field to maximize crop yield. Since different crops are planted in rows having pre-selected row widths, depending on the crop to be grown, the row crop applicator machinery needs to have adjustable track widths such that the tires of the applicator can be driven in the rows defined between the rows of crop. Typical row crop applicators have a track width adjustable between 120 and 152 inches.
Four wheeled row crop applicators have an axle assembly including a tie rod extending between a pair of steering structures for maintaining a pre-selected toe-in setting. Consequently, when the track width of the steering assembly is adjusted in the longitudinal direction, the length of the tie rod needs to be adjusted in the longitudinal direction in step therewith. Prior art steering axle assemblies are typically adjusted hydraulically. However, presently available tie rods are typically comprised of a rod telescopingly received within a tubular member, wherein a set pin can be selectively removed therefrom such that the inner rod member can telescope within the tubular member when the track width is adjusted such as disclosed in U.S. No. 5,121,808 to Visentini et al., issued Jun. 16, 1992 entitled "Adjustable Gauge Steering Axle". One or more set pins are then subsequently reinserted through a pair of holes defined in both the tubular member and the telescoping rod to secure the inner rod to the tubular member. These holes are typically defined in four (4) inch increments, wherein the operator has to manually insert and remove the pins during the track width adjustment procedure.
One major problem with prior art equipment is that the toe-in setting defined by the wheel assemblies needs to be reset whenever the track width is established between a minimum and maximum setting. Further, since the holes in the tie rod assembly are defined every four (4) inches, the operator needs to repeatedly fine tune the track width adjustment until the holes of the inner rod and the outer tubular member are perfectly aligned so that the set pin can be disposed therein. These processes are time consuming, tedious and potentially dangerous as the operator needs to be positioned beneath the front of the tractor chassis. Further, the track width of the row crop applicator can only be adjusted in four (4) inch increments, and is not adjustable in negligible increments. Some crops are planted in rows as narrow as 24 inches, and since the track widths of tractor wheels can sometimes extend up to 12 inches, a four inch track width adjustment increment does not provide adequate fine tuning of a desirable track width.
Typically, independent contractors are hired by the farmer to treat a field. The track width of the contractor's row crop applicator is usually not initially appropriate for the intended field to be treated with fertilizer when the contractor arrives to the field. Thus, the independent contractor is required to adjust the track width, and reset the toe-in. Treating several different fields in a day may require setting several different track widths, which is time consuming and inefficient. When the independent contractor is under severe time limitations to treat many fields with fertilizer in a very narrow time window, which can be dictated by the weather or other uncontrollable circumstances, valuable time is lost during the repeated track width adjustments. Thus, the independent contractor stands to benefit from the present invention. However, even the farm owner can benefit from an improved adjustable tie rod arrangement since the typical farmer plants more than one type of crop, each having different row widths. Hence, having a row crop applicator with an a track width adjustable in increments that are negligible or as large as the overall maximum track width, or any size in between a minimum and maximum track width would benefit the average farmer as well.
The present invention overcomes many of the attendant disadvantages of existing systems by providing a row crop applicator with a steering structure having an adjustable track width, wherein a hydraulically adjustable tie rod can be adjusted in any size increments, while driving the machine, in a secure arrangement between a first and second track width setting, without the need to mechanically lock the steering structure while making the adjustment.
Another feature of the prevent invention is the provision of an adjustable tie rod assembly which will automatically correct for any cylinder drift that could cause the wheel toe-in adjustment to change.